1. Field of the Invention
The invention relates to die rolls of a soft capsule manufacturing apparatus and a method of manufacturing soft capsules using the same wherein a filling material such as liquid medicine is encapsulated by two pieces of gelatin sheet.
2. Description of Related Art
Soft capsules are generally manufactured by a manufacturing apparatus as illustrated in FIG. 10.
The manufacturing apparatus includes a pair of die rolls 10, 10 that are close to and confront each other, a nozzle segment 20 that supplies a filing material and is formed of an inverse mountain-like projection 21 having curved faces that are positioned in confronting relation with each other at right and left sides about the lower end central portion thereof, wherein the projection 21 confronts and is engaged in a curved recess S1 that is formed by surrounding curved peripheral surfaces of the die rolls 10, 10 at the upper sides thereof, and a supply hopper 30 located at the uppermost end thereof.
There are a distributor (dispersion plate) 41 for distributing the filming material, a slide valve mechanism 42 for controlling the supply of the filling material by sliding operation, a tube assembly plate 43 on which pipes for connection with a plurality of tubes are provided upright, and a plunger type pump 50 (hereinafter referred to simply as a pump 50) having a plurality of cylinders, that are respectively interposed between the nozzle segment 20 and the supply hopper 30 in the ascending order, and wherein the plurality of tubes (hoses) 61 for supplying the filling material threrethrough that are provided between the plurality of cylinders of the pump 50 and the tube assembly plate 43. Further, there are provided a return tube (hose) 62 that is interposed between the distributor 41, the slide valve mechanism 42 and the supply hopper 30, for returning the filling material that becomes useless, strip rolls 71, 71 for separating a pair of soft capsules that are provided under and appropriately away from the die rolls 10, 10, and a pair of mangle rolls 72, 72 which draw the pair of gelatin sheets.
When manufacturing the soft capsules, two gelatin sheets 100, 100 are supplied between the pair of rotating die rolls 10, 10 from the upper side thereof at the right and left sides thereof, and the filing material such as liquid medicine is filled in the supply hopper 30, wherein the filling material is supplied to a plurality of nozzle holes 22 that are arranged in one row in a longitudinal direction of the right and left curved faces of the inverse mountain-like projection 21 of the nozzle segment 20 at portions close to the lower end edge (or at the lowermost end edge) through the tubes 61, the tube assembly plate 43, the slide valve mechanism 42 and the distributor 41 when the pump 50 is actuated.
As a result, a plurality of capsule pockets 11 that are provided on the outer peripheral surfaces of the die rolls 10, 10 and arranged axially in a row occupy the nozzle holes 22 of the nozzle segment 20 while they are rotated, and hence the filling material is temporarily stored inside two gelatin sheets 100, 100, and they are conveyed downward with the rotation of the die rolls 10, 10. The gelatin sheets 100, 100 are brought into intimate contact with each other in a moment when the filling material passed through the narrowest part between the die rolls 10, 10, and they are cut and brought into intimate contact with each other under pressure at the same time when the annular blades that are formed at the peripheries of the capsule pockets 11 of the die rolls 10, 10 mesh with each other, so that intended soft capsules 200 are formed.
The thus formed soft capsules 200 that remain stuck to the capsule pockets 11 of the die rolls 10, 10 are stripped off by a brush or the like while the soft capsules 200 that remain stuck to a remaining gelatin sheet 101 formed by bonding two gelatin sheets 100, 100 are separated by the pair of strip rolls 71, 71, and also the remaining gelatin sheet 101 is drawn downward by the pair of mangle rolls 72, 72.
The soft capsules are instantaneously manufactured in practice, wherein the setting of the discharging accuracy of the filling material from the nozzle holes 22 of the nozzle segment 20 and of the timing such as rotation of the die rolls 10, 10 become very important If the discharging accuracy and the timing such as rotation are poorly set, the amount of the filling material filled in the soft capsules 200 is varied or the gelatin sheets 100, 100 are poorly bonded to each other or there occurs the deformation of the shape of the soft capsules 200.
Accordingly, there has been generally employed a pump as the pump 50 shown in FIG. 11, wherein the pump includes a plurality of cylinders 51a, 5lb (respectively five cylinders in this example) that are arranged symmetrically at right and left. Either of the cylinders 51a, 51b corresponds to each nozzle hole 22 of the nozzle segment 20 so as to secure the discharging accuracy, and a timing between the actuating or driving speed of the pump 50 and the rotational speed of the die rolls 10, 10 is accurately provided or set using a timing gear or the like.
For example, a concrete filling state is explained with reference to a case using the plunger 50 shown in FIG. 10, the typical nozzle segment 20 having five nozzle holes 22a to 22e as shown in FIGS. 12 and 13, and a typical right die roll 10 (left die roll 10 is omitted in FIG. 13) having three capsule pockets 11a, 11b and 11c that are arranged along the row denoted by the line A--A and two capsule pockets 11a and 11b are arranged along the row denoted by the line B--B wherein these capsule pockets are repeatedly provided in the circumferential direction.
When the filling material is filled in the three capsule pockets 11a, 11b and 11c that are arranged in the row denoted by the line A--A, all the cylinders 51b provided at the right side of the pump 50 are actuated, while when the filling material is discharged, the nozzle holes 22a, 22c and 22e of the nozzle segment 20 corresponding to the capsule pockets 11a, 11b and 11c are used, whereas the filling material corresponding to the nozzle holes 22b and 22d is returned to the supply hopper 30 through the distributor 41, the slide valve mechanism 42 and the return tube 62.
Meanwhile, when the filling material is filled in the next two capsule pockets 11a and 11b that are arranged in the row denoted by the line B--B, all the cylinders 51b provided at the right side of the pump 50 are actuated, while when the filling material is discharged, the nozzle holes 22b and 22d of the nozzle segment 20 corresponding to the two capsule pockets 11a and 11b are used, whereas the fling material corresponding to the nozzle holes 22a, 22c and 22e are returned to the supply hopper 30 through the distributor 41, the slide valve mechanism 42 and the return tube 62. Such a filling operation is simultaneously operated at the left side of the die roll 10.
Such a discharging process is sequentially repeated by the rotation of the die rolls 10, 10 so as to form intended soft capsules 200.
The standard of the die roll 10 that is practically used is shown in FIGS. 14 to 16. The diameter of each row is 102.8 mm and the length of the axis of each roll is 152.5 mm. The length of the axis of each roll is divided by 29, and the number of capsule pockets (3 rows+2 rows=5 rows) becomes 145. There are defined small gaps 61 and 62 between annular blades 12, 12 formed around the capsule pockets 11 (respective capsule pockets 11a, 11b, 11c and the capsule pockets 11a and 11b) and projections 13, 13 at the right and left ends of the die roll for pressing the edges of the gelatin sheets. Denoted by 61 is the gap defined between the blades 12 and 12 in the circumferential direction and it is 1.33 mm, and 62 is the interval between the blades 12 and 12 in the axial direction and it is 2.7 mm. The width of each blade is 1.0 mm, and the height of the each blade is 0.85 mm.
However, there are following problems in the conventional apparatus for and a method of manufacturing soft capsules, die rolls 10, 10
(1) Although it is preferable that there are many capsule pockets 11 are provided on the die rolls 10, 10, for example, in the case of the die roll having the standard shown in FIGS. 14 to 16, the gaps 61 and 62 are defined between the blades 12 of the capsule pockets 11, leading to the limits in the increase of the number of the capsule pockets 11.
(2) Since there are defined the gaps 61 and 62 between the blades 12, the remaining gelatin sheet 101 is generated as a matter of course. The amount of the remaining gelatin sheet relative to all the amount of the gelatin sheets 100, 100 is normally 35 to 45%. This causes a troublesome problem that the gelatin is inevitably wasted, and it takes a wasting cost, and finally it causes environmental pollution.
(3) Further, the remaining gelatin sheet 101 causes a machine trouble because it becomes a net-shape and it is eventually wound around the die rolls 10, 10 and also around the strip rolls 71, 71 and the mangle rolls 72, 72 that are provided under the die rolls 10, 10, leading to the hindrance of the stable operation.
(4) Meanwhile, it is possible to increase the rotational speed of each die roll to increase the volume of production. However, the driving speed of the pump 50 interlocked with the die roll 10 should be increased to increase the rotational speed of the die roll LO. Since the pump 50 is a plunger type having many mechanical parts in construction, it has a problem or limits in the speeding up.
Particularly, since the capsule pockets 11 are formed to arrange at an equal interval in the circumferential direction of each die roll 10, the number of capsule pockets having less filling amount and arranged in the circumferential direction becomes larger than the number of those having large filling amount, so that even if the rotational speed of the die roll 10 is low, the pump 50 is required to have a relatively high driving speed. Accordingly, the die roll 10 having many capsule pockets in the circumferential direction has a serious problem that it is hardly possible to speed up the rotational speed of the die roll 10 in view of the limits of performance of the pump 50.
(5) If the driving speed of the pump 50 increases, the filling accuracy is lowered, causing a problem of the deterioration of the soft capsules.
(6) When the rotational speed of the die roll 10 and the driving speed of the pump 50 respectively increase, a mechanical load applied to the apparatus increases, causing a problem that a trouble is liable to occur so that the apparatus can not be used for a long period of time.
(7) Although it is possible to increase the number of capsule pockets in the axial direction using the die roll 10 having a long axis, it causes a problem that the entire apparatus as well as the die roll per se costs high.
Under the circumstances having the various problems, the inventor of this application endeavored himself to improve the productivity and to study the cause of the generation of the remaining gelatin sheet 101 that is consumed in vain or wasted, then he has found out that two gelatin sheets 100, 100 are firmly bonded to each other at each edge of the traces of capsules (holes) of the remaining gelatin sheet 101 from which the soft capsules 200 are cut.
The inventor experimentally manufactured the soft capsules using a die roll having a single blade between two capsule pockets, namely, using the die roll having a single blade that is shared by adjacent capsule pockets. As a result, it has been found that there is no problem if the driving speed of the pump 50, the rotational speed of the die rolls 10, 10 and the shape of the curved surfaces that are opened to form the nozzle holes 22 of the nozzle segment 20 are optimally adjusted, and also found that the remaining gelatin sheet causing the machine trouble can be sharply reduced.